Toyota Jidosha Kabushiki Kaisha

Denso Corporation

Masayoshi Hattori

Tsukasa Abe

Yasumichi Inoue

Noboru Takagi

Zenichiro Mashiki

Daigo Ando

Haruyuki Urushihata

Masaomi Inoue

Kenji Yamamoto

Yuuichi Takemura

Toshikazu Tanaka

Eiichi Hioka

An idling-time target phase setting unit () variably sets a target phase based on a target idle speed that is set by a target idle speed setting unit. () Especially, when the target idle speed is lower than a predetermined rotational speed and operating noise of a variable valve timing mechanism () is easily heard by, for example, a driver, the.idling-time' target phase setting unit () sets the target phase so that a range, in which the valve phase is allowed to change, is restricted within a phase region where a speed reduction ratio is high and the operating noise is relatively low.

Control unit and control method for variable valve timing mechanism

An ECU executes a program based on which, when a fuel-supply cutoff control is executed or when a hybrid vehicle travels in a second mode in which the engine is stopped and the hybrid vehicle travels using only the drive power generated by a second MG an intake VVT mechanism is controlled so that a valve phase is brought to the mechanically determined most retarded phase. The phase, which is detected by a cam position sensor, is learned as the most retarded phase.

Control unit and control method for variable valve timing mechanism, program for implementing the control method, and recording medium on which the program is recorded

A stop-time target phase setting unit sets a target phase CAr for an intake valve to a target phase, which is used when an engine is stopped, in response to issuance of an engine stop command. An engine stop control unit generates a series of control commands for an engine stop process in response to issuance of the engine stop command. A motoring command unit generates a first MG control command for rotating the engine using a motor for a predetermined period Tm that is counted by a timer in response to issuance of the engine stop command. Thus, the engine idles even after fuel combustion stops. In this way, the period in which the valve phase can be changed by a VVT mechanism is increased. As a result, a valve phase when the engine stops is reliably brought to the target phase that is suitable for next engine starting.

Control unit for variable valve timing mechanism

In an intake valve phase control after an engine stop command is issued, a stop-time phase is used as a target value. In the intake valve phase control, when the mode changeover condition is not satisfied, and an electric motor that serves as an actuator is not in a locked-state, the highest-speed mode, in which the amount of electric power supplied to the electric motor is fixed to the maximum value, is selected to reliably change the intake valve phase by a required amount. Then, the intake valve phase comes close to the stop-time phase and the mode changeover condition is satisfied, the control mode is changed from the highest-speed mode to the normal mode to set the control phase to the stop-time phase with higher accuracy, and the feedback control over the intake valve phase is executed.

Variable valve timing system and method for controlling the same

An actuator operation amount setting unit prepares the rotational speed command value for an electric motor such that the phase of an intake valve changes in accordance with the target phase. An electric-motor EDU controls the motor supply electric power such that the electric motor operates in accordance with the rotational speed command value. An overheating determination unit determines whether at least one of the electric motor and the electric-motor EDU needs to be restricted from heating up based on a result of comparison between the information indicating the motor supply electric power and the reference value. A rotational speed command value restriction unit restricts the rotational speed command value provided to the electric-motor EDU to a value within a predetermined range, when it is determined that the at least one of the electric motor and the electric-motor EDU needs to be restricted from heating up. A reference value setting unit variably sets the reference value based on the rotational speed of the electric motor.

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Toyota, Japan

Masayoshi Hattori